This invention relates to micro-actuators usable to produce controlled movements.
U.S. Pat. No. 2,896,507 describes an imaging member which includes an elastically deformable layer sandwiched between a pair of electrode plates. In operation, an electrical field is established across the deformable layer, thus causing this layer to deform. The deformation produces relative movement between the electrode plates. U.S. Pat. No. 3,716,359 discloses improved thin flexible metallic layer electrode plates comprising a plurality of different metals such as, for example, gold, indium, aluminum, silver, magnesium, copper, cobalt, iron, chromium, nickel, gallium, cadmium, mercury, and lead. Various techniques for forming the metallic layers on the elastomer layer are described including, for example, by vacuum evaporation. U.S. Pat. No. 4,163,667 describes the use of a composition of titanium and silver for use as the flexible conductive metallic layer electrode plates in imaging members.
It has been found that using solid elastomer material for the elastically deformable layer does not produce a significant amount of relative movement between the pair of electrode plates in response to the application of a reasonable electrical field because there is very little change in the volume of the elastomer. According to a feature of the present invention, the provision of a significant amount of free space or voids in the elastically deformable layer increases the relative motion of the pair of electrode plates.
It is an object of the present invention to provide a deformable micro-actuator of an elastomer material that produces a significant amount of relative movement between the pair of electrode plates in response to the application of a reasonable electrical field.
It is another object of the present invention to provide a deformable micro-actuator of an elastomer material having a significant amount of free space or voids in the elastomer material such that a significant amount of relative movement between the pair of electrode plates is produced in response to the application of a reasonable electrical field.
According to a feature of the present invention, a micro-actuator has a pair of conductive metallic layers connectable to an electrical potential source so as to induce a force between the metallic layers upon application of an electrical field. A layer of dense elastomer material is sandwiched between the pair of conductive metallic layers such that there will be a change in the volume of the elastomer material in response to relative movement between the conductive metallic layers. The elastomer material has at least one void within the elastomer material, whereby the micro-actuator exhibits void-enhanced growth and reduction in size in response to the effected force induced by the applied electrical field.
In a preferred embodiment of the present invention at least one of the metallic layers is a flexible electrode plate. The other metallic layer may be rigid and essentially non-deformable. The elastomer material has substantial plurality of voids.
The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiments presented below.